1. Technical Field
The present invention relates to a cathode ray tube providing increased protection from electric shock and providing reduced emission of electromagnetic waves, and more particularly, to a cathode ray tube with a panel that provides increased protection from electric shock and provides reduced emission of electromagnetic waves, and a method for manufacturing the cathode ray tube.
2. Related Art
In order to scan the phosphor layer formed on an inner surface of a panel of a cathode ray tube (CRT) with electron beam, a high voltage is applied across a cathode and anode, causing the anode button to have a positive electric potential. The inner portion of the panel also has a positive electric potential because the anode button is connected with an aluminum film on the panel. As a result, a high negative electric potential is formed on the outer surface of the panel, which may give electric shocks to a user. To avoid this danger, the surface of the panel must be grounded.
We have found that it can be a challenge to design and manufacture an improved apparatus to avoid this danger. Efforts have been made to improve cathode ray tubes.
Exemplars of recent efforts in the art include U.S. Pat. No. 5,025,490 issued to Tamura entitled CATHODE-RAY TUBE WITH ITS DISPLAY FRONT PROTECTED FROM UNDESIRABLE ELECTRIFICATION, Japanese Patent Publication No. 04-174945 entitled ANTISTATIC TYPE CATHODE-RAY TUBE listing inventors Hirasawa et al., Japanese Patent Publication No. 05-041187 entitled CATHODE RAY TUBE listing inventors Takamura et al., Japanese Patent Publication No. 08-287850 entitled CATHODE-RAY TUBE, DISPLAY UNIT, AND MANUFACTURE OF CATHODE-RAY TUBE listing inventors Saito et al., and Japanese Patent Publication No. 09-213244 entitled PANEL FOR CATHODE-RAY TUBE AND ITS MANUFACTURE listing inventors Imamura et al.
While these recent efforts provide advantages, I note that they fail to adequately provide a cathode ray tube with a panel that provides increased protection from electric shock and provides reduced emission of electromagnetic waves, and a method for manufacturing the cathode ray tube.
To solve the above problems and others, it is an objective of the present invention to provide a cathode ray tube whose panel provides increased protection from electric shock and reduced emission of electromagnetic waves by completely grounding a conductive film of a multi-layered film formed on an outer surface of a panel portion of a cathode ray tube (CRT), while not damaging the multi-layered film and an electrode.
To solve the above problems and others, it is an objective of the present invention to provide a manufacturing method of a cathode ray tube whose panel provides increased protection from electric shock and reduced emission of electromagnetic waves by completely grounding a conductive film of a multi-layered film formed on an outer surface of a panel portion of a cathode ray tube, while not damaging the multi-layered film and an electrode.
To achieve the above objectives and others, according to one embodiment, there is provided a cathode ray tube for preventing electrification and shielding electromagnetic waves wherein a transparent conductive film is formed on the outer surface of a panel portion and a transparent insulating protective film is formed on the transparent conductive film. The cathode ray tube includes an electrode formed on at least a part of an inactive screen and on sides of the panel portion before the transparent conductive film and the transparent insulating protective film are coated, and a conductive tape coated with a conductive adhesive for electrically connecting the electrode and an explosive-proof band.
At this time, it is preferable that the electrode is formed by applying conductive colloid or paste on the inactive screen of the panel portion. Also, the conductive colloid or paste preferably comprises particles of silver, gold, copper, nickel, palladium, platinum, ruthenium, or aluminum, or ruthenium oxide particles, or graphite or carbon black particles or fibers.
The electrode may be in direct contact with an explosive-proof band, and in this case, a general adhesive tape can be used instead of the conductive tape.
It is preferable that the conductive tape electrically connects the electrode with the explosive-proof band and at the same time, covers the transparent insulating protective film on the inactive screen of the panel portion in order to protect the electrode.
The above objectives and others can be also achieved by a method for manufacturing a cathode-ray tube for preventing electrification and shielding electromagnetic waves, comprising the steps of: applying conductive colloid or paste on at least a part of an inactive screen and on sides of a panel portion; coating the entire surface of the panel portion with a transparent conductive film and a transparent insulating protective film; sintering and hardening the surface of the panel portion; and attaching a conductive tape coated with a conductive adhesive to a formed electrode and connecting the conductive tape to an explosive-proof band.
At this time, it is preferable that the conductive tape covers the transparent insulating protective film on the inactive screen of the panel portion.
To achieve the above objectives and others, according to another embodiment, there is provided a cathode ray tube for preventing electrification and shielding electromagnetic waves including a transparent conductive film coated on the outer surface of a panel portion; a transparent insulating protective film coated on the transparent conductive film; an electrode formed on the outer surface of a panel portion by removing the transparent conductive film and the transparent insulating protective film on an inactive screen of the panel portion; and a conductive tape coated with a conductive adhesive electrically connecting the electrode and an explosive-proof band.
At this time, the electrode is preferably formed by applying conductive colloid or paste on the inactive screen of the panel portion. Also, the conductive colloid or paste preferably comprises particles of silver, gold, copper, nickel, palladium, platinum, ruthenium or aluminum, or ruthenium oxide particles, or graphite or carbon black particles or fibers.
Also, the electrode may be in direct contact with the explosive-proof band, and in this case, a general adhesive tape can be used instead of the conductive tape.
It is preferable that the conductive tape connects the electrode with the explosive-proof band and at the same time, covers the transparent insulating protective film on the inactive screen of the panel portion to protect the electrode.
To achieve the above objectives and others, there is provided a method for manufacturing a cathode-ray tube for preventing electrification and shielding electromagnetic waves including the steps of: coating the entire surface of a panel with a transparent conductive film and a transparent insulating protective film on the conductive film; forming an electrode by removing at least a part of the multi-layered film on an inactive screen of the panel portion and at the same time, applying conductive colloid or paste on the inactive screen where the multi-layered film is removed and on the sides of the panel; sintering and hardening the surface of the panel; and attaching a conductive tape coated with a conductive adhesive to the formed electrode and connecting the conductive tape to an explosive-proof band.
At this time, it is preferable that the conductive tape is applied to cover the transparent insulating protective film on the inactive screen of the panel portion.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a cathode ray tube apparatus, comprising: a cathode ray tube having a panel portion; a first film being formed on an outer surface of the panel portion, said first film being transparent and conductive; a second film being formed on said first film, said second film being transparent and insulating; and an electrode being formed on at least a part of the panel portion before said first and second films are formed, said electrode being electrically connected to an explosive-proof band.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a method, comprising: applying at least one selected from among a conductive colloid and a conductive paste on at least a part of an inactive screen portion and on sides of a panel portion of a cathode ray tube device; coating an entire surface of said panel portion with a transparent conductive film and with a transparent insulating protective film; sintering and hardening said surface of said panel portion; and attaching a conductive tape coated with a conductive adhesive to a formed electrode and connecting said conductive tape to an explosive-proof band.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a cathode ray tube apparatus for preventing electrification and shielding electromagnetic waves, the apparatus comprising: a transparent conductive film being coated on an outer surface of a panel portion; a transparent insulating protective film being coated on said transparent conductive film; an electrode being formed on the outer surface of the panel portion by removing said transparent conductive film and said transparent insulating protective film on an inactive screen portion of the panel portion; and an adhesive tape adhering to said electrode and an explosive-proof band.
To achieve these and other objects in accordance with the principles of the present invention, as embodied and broadly described, the present invention provides a method for manufacturing a cathode-ray tube for preventing electrification and for shielding electromagnetic waves, the method comprising: coating a surface of a panel with a transparent conductive film, and coating a transparent insulating protective film on said transparent conductive film, to form a multi-layered film; forming an electrode by substantially simultaneously removing at least a part of the multi-layered film on an inactive screen portion of the panel and applying one of a conductive colloid and a conductive paste on the inactive screen portion where the multi-layered film is removed and on sides of the panel; sintering and hardening the surface of the panel; and attaching a conductive tape coated with a conductive adhesive to the formed electrode and connecting the conductive tape to an explosive-proof band.
The present invention is more specifically described in the following paragraphs by reference to the drawings attached only by way of example. Other advantages and features will become apparent from the following description and from the claims.